A COMBINED MAGNETOOPTIC MAGNETIC FORCE MICROSCOPE STUDY OF CO PD MULTILAYER FILMS/

We have combined a magnetic force/atomic force microscope (MFM/AFM) wi th a magneto-optic (MO) microscope. This instrument combines the high spatial resolution of the MFM/AFM and its capability to correlate magn etic structure with the structure of the sample surface with the real- time imaging capabilities and large field of view of the MO microscope . Our MO/MFM setup is based on the Nanoscope III Multimode(TM) MFM/AFM (Digital Instruments, Santa Barbara, CA). Currently, the spatial reso lution of the MO microscope is about 3 mu m and polarization sensitivi ty is on the order of 0.5 degrees. Using this instrument, we observed domain structures in Co/Pd multilayer films. We found that in a film w ith 20 Co/Pd layer pairs and 16 nm total thickness, nucleation of doma ins during sample remagnetizations occurs repeatedly in the same point s, and that displacement of domain walls is unidirectional. The high t opographic resolution of the AFM allowed us to show that domains nucle ate at small defects on the sample surface. The depth of the defects i s 1-2 nm, they are 20-30 nm wide and up to 500 nm long. The unidirecti onal displacement of the domain walls was found to correlate with the anisotropic structure of the sample surface. (C) 1997 American Institu te of Physics.